VGA sync circuit

you registered h_sync and v_sync output to avoid glitches.

-- mod-800 horizontal sync counter

process(h_count_reg,h_end,pixel_tick)

begin

if (pixel_tick='1') then --25 MHz tick

if h_end='1' then

h_count_next <= (others=>'0');

else

h_count_next <= h_count_reg+1;

end if;

else

h_count_next <= h_count_reg;

end if;

end process;

-- mode-525 vertical sync counter

process(v_count_reg,h_end,v_end,pixel_tick)

begin

if (pixel_tick='1' and h_end='1') then

if (v_end='1') then

v_count_next <= (others=>'0');

else

v_count_next <= v_count_reg+1;

end if;

else

v_count_next <= v_count_reg;

end if;

end process;